1. Field of the Invention
This disclosure relates to a lens array, and is suitable for a lens array used, for example, in an imaging apparatus, or an image reading apparatus.
2. Description of the Related Art
Recently, imaging apparatuses and image reading apparatuses using a lens array composed of a small diameter lens array have been developed. In this configuration, reductions in the size and cost of the apparatus may be realized in comparison with a configuration in which a photosensitive member is scanned using by a polygon mirror and a configuration in which images are readby using a plurality of lenses or mirrors.
However, such a lens array has a problem that unevenness of light amount distribution in image formation (unevenness of light amount distribution) may develop on an image plane (which corresponds to a sensor plane in an image reading apparatus, and to a photosensitive plane in an imaging apparatus). When unevenness of light amount distribution develops, formed images formed by the imaging apparatus and read images read by the image reading apparatus may be formed with stripes and consequently, degradation of the image quality of the formed images and the read images may result.
Technologies for solving the problem described above are proposed in US2006/0176361 and Japanese Patent Laid-Open No. 2002-318348. A configuration in which light-emitting intensities of respective light-emitting elements of a light source array are modulated to reduce the unevenness of light amount distribution is disclosed in US2006/0176361. A configuration in which an array pitch of respective imaging units which constitute a lens array is set to a value in an appropriate range to reduce the unevenness of light amount distribution is disclosed in Japanese Patent Laid-Open No. 2002-318348.
However, even though the unevenness of light amount distribution is reduced by the configurations disclosed in US2006/0176361 and Japanese Patent Laid-Open No. 2002-318348, if a change (deformation or a change of refractive index) occurs in the respective imaging portions which constitute the lens array due to a temperature change or the like, the unevenness of light amount distribution may show up again on the image plane.